An organic electroluminescent device has a multilayer structure comprising (i) a luminescent layer comprising a light emitting compound, (ii) a hole transport layer and an electron transport layer, which sandwich the luminescent layer, and (iii) an anode and a cathode, which sandwich the hole transport layer, the luminescent layer and the electron transport layer. The organic electroluminescent device utilizes light emission (fluorescence or phosphorescence) occurring at deactivation of an exciton formed by the recombination of electron with hole, which are injected in the luminescent layer. Utilizing this feature, the organic electroluminescent device is applied to displays and others.
The 1,3,5-triazine derivative according to the present invention is novel and characterized as having quarterarylenyl groups having a pyridyl group in 2- and 4-positions of the 1,3,5-triazine ring, and an aromatic hydrocarbon group in a 6-position thereof.
Recently, various 1,3,5-triazine derivatives for use in an organic electroluminescent device have been proposed (see, for example, patent documents 1 to 4). These proposed triazine derivatives have 2,4-di-substituted phenyl groups or 3,4-di-substituted phenyl groups in 2-, 4- and 6-positions of a triazine ring, and thus, are distinguished from the 1,3,5-triazine derivative of the present invention, which has quarterarylenyl groups having a pyridyl group in 2- and 4-positions of the 1,3,5-triazine ring.
Further, 1,3,5-triazine derivatives for use in an organic electroluminescent device have been proposed (see, for example, patent documents 5 and 6). These proposed triazine derivatives have substituted phenyl groups in 2-, 4- and 6-positions of a triazine ring, but, the positions in the phenyl groups in which substituents are bonded to the phenyl groups are indefinite. The 1,3,5-triazine derivative of the present invention, which has quarterarylenyl groups having a pyridyl group, in 2- and 4-positions of the 1,3,5-triazine ring, is not described in these patent documents.
A triazine derivative having in the triazine ring quaterarylenyl groups containing pyridyl groups, for use in an organic electroluminescent device, have been proposed (see, for example, patent document 7). The proposed triazine derivative has quaterarylenyl groups, each chain end of which is bonded to the triazine ring of the triazine derivative. Thus, the proposed triazine derivative is distinguished from the 1,3,5-triazine derivative of the present invention, which has quarterarylenyl groups bonded to the 1,3,5-triazine ring in the midway of each quarterarylenyl group.
Still another 1,3,5-triazine derivative for use in an organic electroluminescent device has been proposed (see, for example, patent document 8). The proposed triazine derivative has 3,5-di-substituted phenyl group in a 2-position of the triazine ring, and thus, is distinguished from the 1,3,5-triazine derivative of the present invention,